In the past, providing advanced communications features to large companies with facilities at different locations required interconnection of a number of privately owned exchanges. U.S. Pat. No. 4,802,199 issued Jan. 31, 1989, to Michael D. Lange et al., for example, discloses a multiple exchange system aimed at the needs of large customers having facilities at a number of different geographic locations. The system provides repertory dialing through the switched network to set up connections between the different PBXs to emulate a dedicated private line connection. The system supports speed or repertory dialing, SMDR reporting and automatic routing features. The requisite processing capability for setting up the virtual private line connections between exchanges and providing special service features is located in the individual private exchanges. For example, the SMDR data acquisition apparently occurs on a switch by switch basis; each switch accumulates SMDR data in response to a subscriber accessing the virtual facility through that switch (column 4, lines 35-65). The problem with this approach is that the company must own, operate and maintain some form of private exchange at each of its locations. Also, in the Lange et al. system, the exchanges are PBXs interconnected via public or private switched network lines, and the company incurs the expense of these lines as well.
Rather than providing business services through a private exchange, such as a PBX, Centrex takes a group of normal telephone lines and provides call processing to add business features to the otherwise standard telephone lines. For example, the Centrex exchange adds intercom capabilities to the lines of a specified business group so that a business customer can dial other stations within the same group using extension numbers, such as a two, three or four digit numbers, instead of the full telephone number associated with each called line or station. Other examples of Centrex service features include call transfer between users at different stations of the business group, a number of varieties of call forwarding and speed calling. Clearly Centrex adds a bundle of business features on top of the standard telephone line so that whatever a station or communication equipment a customer places on that line will interact with the business system features.
Thus Centrex is a package of features that are placed or added onto the standard service provided via telephone lines that allow a group of lines assigned to a business customer to operate as a business system Centrex typically provides business services similar to those provided by a PBX or PABX through a central office exchange of the public telephone network but without requiring the customer to purchase and maintain a private exchange.
A problem with the existing Centrex is illustrated by call transfer. In the existing service, a business customer receives a call on one line but decides the caller should talk to an employee on another line. The currently connected individual could flash the switch hook and dial the second employee's extension number and hang up. The call is transferred by the central office over to the line of the second employee. If provided by a prior art Centrex, the transfer is confined to one central office. Consequently, the transfer feature works only so long as all of the employees of the particular business customer are served by the same central office.
One way the problem of multiple locations has been addressed in the past is for the customer to purchase private tie lines to connect remote facilities to the customer's exchange. In effect, when a remote employee wanted to call through the network to another employee, the remote employee took the station set off-hook and the set connected through a tie line to the distant exchange which provides the customer with the Centrex service. The calling employee then received the dial tone of the distant exchange via the tie line. Use of such private lines, however, incurs mileage charges for the wires strung from the exchange to each distant extension. Using digital switches, to achieve a similar result requires deployment of a remote switching module at the remote locations to supply foreign dial tone and connect the remote switching modules to the distant exchange via a fiber optic trunk. Every prior art system for extending Centrex type services to distant customer facilities therefore does involve some form of private line to the remote locations.
Another problem relating to existing business services is illustrated by call routing. This type of service for outgoing calls selects one of three different line or trunk groups to place a call through. For a call from one city going to a distant city there might be a choice of going first via a Tie line, second to MCI and then to some kind of AT&T WATS line. Typically, a customer uses such call routing to control communication costs. The selection is made on a priority basis established by the customer in whatever manner produces the most economical use of their facilities. In the existing network, however, such call routing is controlled at the central office level of the network. The route selection priority for each Centrex line is programmed in the central office to which the line connects, and changing the priority for any given line requires a technician to go out to the exchange switch and change the wiring and/or programming of that particular switch. Thus, if a business customer has multiple geographic locations connected to different central offices, if the customer desires to change the call routing priority for all locations, technicians would have to modify wiring and/or install another program table in each central office.
Where the customer has a large number of lines to stations dispersed over a variety of geographic locations, typically a number of lines connect to one local central office and other lines connect to one or more remotely located central offices. In such a situation, some services, such as the call transfer discussed above, cannot be provided for all lines. Also, those services that can be provided require extensive programming and/or wiring at each connected central office switch to establish or change the service parameters as was discussed above with regard to call routing. Thus clearly a need exists for providing business type features to customers with facilities at a number of geographically diverse locations through the public telephone network.
In recent years, a number of new service features have been provided by an Advanced Intelligent Network (AIN). In an AIN type system, central offices send and receive data messages from an Integrated Services Control Point (ISCP) via a Switching Transfer Point (STP). At least some calls are then controlled through multiple central office switches using data retrieved from a data base in the ISCP. The prior development of an AIN, however, has concentrated on specific service features which are quite different from Centrex and have not extended Centrex type groups of business features to customers with facilities at a number of geographically diverse locations through the public telephone network.
U.S. Pat. No. 4,756,020 issued Jul. 5, 1988, to Joseph V. Fodale, for example, suggests access authorization in a multiple office environment. The Fodale system restricts access to a long distance telephone network based on the status of the billing number associated with the call, i.e. delinquent. The access control is provided through multiple local and toll offices but is centrally controlled by a data base which stores account status information. The local office serving a calling telephone extends a toll call to the toll office of the toll network carrier. The toll office queries the data base via a CCIS link regarding the current status of the customer's account identified by the billing number associated with the call. The data base obtains the status information of the billing number in question and translates that status into a response message instruction to allow or disallow extension of the toll call through the toll network. The data base transmits the response message to the toll office via CCIS link, and the toll office disallows or extends the call through the toll network as instructed by the response message.
A number of the features provided by the prior art AIN type intelligent networks relate to specialized call processing of incoming calls, as discussed below.
U.S. Pat. No. 4,191,860 issued Mar. 4, 1980, to Roy P. Weber discloses a system for providing special processing of incoming calls via a number of local switching offices based on information stored in a central data base. The local and toll offices of the telephone network compile a call data message and forward that message via a CCIS link to the central data base, essentially a Service Control Point or SCP. The data base at the SCP translates the dialed INWATS number, included in the message, into a call control message. The call control message includes an unlisted destination telephone number, which is then returned to the offices of the network via CCIS link. The network uses the call control message to complete the particular call.
U.S. Pat. Nos. 4,611,094 and 4,611,096 both to Asmuth et al. (hereinafter Asmuth et al.) disclose a system for providing custom incoming telephone call processing services to a corporate customer operating at geographically dispersed locations through a plurality of local office switches. A customer program stored in a central data base is accessed to provide instructions to the switches to complete incoming calls to customer locations in accord with special services defined by the corporate customer. Incoming calls to the customer are routed to an Action Control Point (ACP) which typically is a modified toll office. The ACP has a number of "primitive" call processing capabilities, such as providing voice prompts to callers and receiving additional caller inputs. The customer program controls the ACP's to string together the desired primitive call processing capabilities to process each call to the customer. Specified parameters stored in the program, such as time of day, caller location and data inputs responsive to the voice prompts, determine the final customer station to which each call should be completed. The customized call processing disclosed by Asmuth et al. can also include customized billing for calls, e.g, by splitting charges between the customer and the caller. The Asmuth et al. system sets up a billing record for each call in the ACP or toll office. Asmuth et al. also teach procedures for handling of calls directed to a corporate customer when the call serving office does not have all of the capabilities needed for processing the call in accord with the customer's stored program. In particular, upon recognition of the deficiencies of the call serving office, the Asmuth et al. system transfers call processing to a second office having adequate capabilities for completion of the call.
U.S. Pat. No. 4,788,718 issued Nov. 29, 1988, to Sandra D. McNabb et al. suggests centralized recording of call traffic information. The architecture is similar to that disclosed by the earlier discussed patents to Weber and Asmuth et al. to the extent that local and toll offices communicate with a central data base via CCIS link. The McNabb et al. system improves over the incoming call routing provided by the Weber patent and the two Asmuth et al. patents discussed above by adding a data gathering function to the centralized data base which stores the individual customer's call routing program. In McNabb et al. the central data processor provides call attempt records and a traffic data summary of all calls directed to a particular 800 number.
U.S. Pat. No. 4,757,267 issued Jul. 12, 1988, to Bernard J. Riskin discloses routing of an 800 number call, where the dialed number identifies a particular product or service, to the nearest dealer for the identified product or service. The toll office sends a message including the dialed 800 number and the area code of the caller to a data base which translates this into a standard ten digit telephone number for the nearest computer at a Customer/Dealer Service Company (CDSC). The telephone network then routes the call to this computer, which answers the call and provides a synthesized voice response. The computer uses call data and or Touchtone dialed information from the caller to identify the selected product or service and then accesses its own data base to find the telephone number of one or more nearby dealers in that product or service. The computer then calls the dealer and connects the original caller to the called dealer.
Several other patents use a network similar to the AIN type intelligent network to provide personalized services to individual subscribers, for example when they are away from their home telephone station.
U.S. Pat. No. 4,313,035 issued Jan. 26, 1982, to David S. Jordan et al. patent discloses a method of providing a person locator service through multiple exchanges of the switched telephone network. Each subscriber is assigned a personal number uniquely identifying the subscriber. An absent subscriber inputs a number to which calls are to be completed, such as the number where the subscriber can be reached, into a central data base. A caller wishing to reach the subscriber dials the number uniquely identifying that subscriber. In response to an incoming call directed to the unique number, a telephone switching office having access to CCIS sends the dialed number to the central data base referred to by Jordan et al. as an SSP. The data base retrieves the stored completion number for the called subscriber and forwards that number back to the switching office to complete the call. The subscriber can update the stored data from any telephone. Also, the subscriber can specify whether to charge calls via the person locator system to the subscriber or to the caller.
U.S. Pat. No. 4,899,373 issued Feb. 6, 1990, to Chinmei Lee et al. discloses a system for providing special telephone services to a customer on a personal basis, when the customer is away form his or her home base or office. A nationally accessible data base system stores feature data in association with personal identification numbers. A subscriber wishing to use personalized features while away from home base dials a special code from a station connected to any exchange which has access to the data base and presents the personal identification number. The corresponding feature data is retrieved from the data base and stored in the exchange in association with the station from which the request was initiated. The exchange then provides telephone service corresponding to the subscriber's personalized telephone features. A temporary office arrangement may be established in which the personalized features will be immediately available on incoming and outgoing calls for a period of time specified by the subscriber.
The prior art does not suggest extending the full range of Centrex type services to groups of lines assigned to business customers with facilities at a number of geographically diverse locations, without resort to private line connections between dispersed customer facilities.